I'm looking into doing my own HRV installation and want to run regular (non insulated) galvanized duct in the attic and then add R20 of blown cellulose insulation over the ductwork and the entire attic area. This is part of an insulation & ventilation upgrade in a 35 yr. old home.

Any concerns with this arrangement?

My current air change per hour is .085 compared to .3 minimum reccomened.......and we have all new windows yet to be installed......which will hopefully be more airtight than original windows.

I live in Canada so cold winter temps are a concern with condensation etc.
This will only be a ventialtion installation.....and will not be for AC or heat.